The present invention relates to a hidden sliding track assembly for drawer or the like and more particularly, to a sliding rail coupling structure for hidden sliding track assembly, which supports and stabilizes relative sliding movement between the outer sliding rail and the intermediate sliding rail, and has a high structural strength to support a heavy load.
US2005/0231083A1 teaches the use of two sliding bearing bushes between an intermediate sliding rail and an outer sliding rail and two support rollers in the intermediate sliding rail to support and guide movement of the intermediate sliding rail relative to the outer sliding rail. As illustrated in FIG. 1, two sliding bearing bushes 91 and 92 are provided at the top side of the Intermediate sliding rail 90, and two support rollers 93 and 94 are respectively pivotally provided at the two opposite lateral sides of the intermediate sliding rail 90. This design still has drawbacks as follows
1. The rolling cylinders 95 that are mounted in the two opposite sidewalls of the sliding bearing bushes 91 and 92 are respectively disposed in direct contact with the two opposite sidewalls 901 and 902 of the intermediate sliding rail 90 without any guide means. Therefore, the sliding movement of the intermediate sliding rail 90 relative to the outer sliding rail (not shown) is less stable.
2. The fabrication of the intermediate sliding rail 90 is complicated. During fabrication, the prepared metal sheet material is rolled into shape by means of a roll forming mill (see FIG. 2), and then the left and right sidewalls 901 and 902 of the rail are punched to provide a respective through hole 903 and 904 (see FIG. 3), and then the two through holes 903 and 904 are processed to provide a respective pivot axle 9031 and 9041 (see FIG. 4) for supporting the aforesaid support rollers 93 and 94 (see FIG. 1). This fabrication procedure is complicated, wasting much labor and time.
3. The structural strength of the intermediate sliding rail 90 is not sufficient to support a heavy load.
The present invention has been accomplished under the circumstances in view. It is one object of the present invention to provide a sliding rail coupling structure for hidden sliding track assembly, which supports and stabilizes relative sliding movement between the outer sliding rail and the intermediate sliding rail. It is another object of the present invention to provide a sliding rail coupling structure for hidden sliding track assembly, which has a high structural strength to support a heavy load. It is still another aspect of the present invention to provide a sliding rail coupling structure for hidden sliding track assembly, which saves much manufacturing labor and time.
According to one aspect of the present invention, the sliding rail coupling structure comprises an outer rail, an intermediate sliding rail slidable in and out of the outer rail and having two longitudinal sliding grooves at two sides, sliding bearing bushes coupled to and movable along the intermediate sliding rail, each sliding bearing bush holding a plurality of roller cylinders that are kept in contact between the top wall of the intermediate sliding rail and the top wall of the outer sliding rail and a plurality of rolling balls that are respectively kept in contact between the longitudinal sliding grooves of the intermediate sliding rail and the sidewalls of the outer sliding rail, a roller holder affixed to the intermediate sliding rail to support two support rollers that are respectively in contact with two bottom flanges of the outer sliding rail. The longitudinal sliding grooves of the intermediate sliding rail guide and stabilize movement of the rolling balls.
According to another aspect of the present invention, the intermediate sliding rail has two longitudinal reinforcing grooves respectively formed on the two sidewalls to reinforce the structural strength.
According to still another aspect of the present invention, the roller holder can be made of a metal material by means of a stamping technique, facilitating the fabrication of the roller holder and the mounting of the support rollers and saving much the device cost.